linux-kernel - [PATCH 4/7] drm/bridge: tc358768: Support non-continuous clock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251021-tc358768-v1-4-d590dc6a1a0c@ideasonboard.com>
Date: Tue, 21 Oct 2025 16:23:00 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Parth Pancholi <parth.pancholi@...adex.com>, 
 Francesco Dolcini <francesco.dolcini@...adex.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 Tomi Valkeinen <tomi.valkeinen@...asonboard.com>, 
 Dmitry Osipenko <digetx@...il.com>
Subject: [PATCH 4/7] drm/bridge: tc358768: Support non-continuous clock

The driver prints a warning if MIPI_DSI_CLOCK_NON_CONTINUOUS is set, and
falls back to continuous clock mode. This was added in commit
fbc5a90e82c1 ("drm/bridge: tc358768: Disable non-continuous clock mode").

However, there have been multiple changes to the driver since then, and
at least in my setup, non-continuous clock mode works: I can see an
image on the panel, and I can see the clock lanes being non-continuous
with an oscilloscope.

So, let's enable MIPI_DSI_CLOCK_NON_CONTINUOUS support.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Cc: Dmitry Osipenko <digetx@...il.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 755ed6483b2e..a276fbc75dde 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -722,7 +722,6 @@ static void tc358768_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 {
 	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
 	struct mipi_dsi_device *dsi_dev = priv->output.dev;
-	unsigned long mode_flags = dsi_dev->mode_flags;
 	u32 val, mask, val2, lptxcnt, hact, data_type;
 	s32 raw_val;
 	struct drm_crtc_state *crtc_state;
@@ -744,11 +743,6 @@ static void tc358768_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 	u32 dsi_vsdly;
 	const u32 internal_dly = 40;
 
-	if (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
-		dev_warn_once(dev, "Non-continuous mode unimplemented, falling back to continuous\n");
-		mode_flags &= ~MIPI_DSI_CLOCK_NON_CONTINUOUS;
-	}
-
 	tc358768_hw_enable(priv);
 
 	ret = tc358768_sw_reset(priv);
@@ -1032,7 +1026,7 @@ static void tc358768_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 	tc358768_write(priv, TC358768_HSTXVREGEN, val);
 
 	tc358768_write(priv, TC358768_TXOPTIONCNTRL,
-		       (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) ? 0 : BIT(0));
+		       (dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) ? 0 : BIT(0));
 
 	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
 	val = tc358768_ps_to_ns((lptxcnt + 1) * hsbyteclk_ps * 4);
@@ -1099,7 +1093,7 @@ static void tc358768_bridge_atomic_pre_enable(struct drm_bridge *bridge,
 
 	val |= TC358768_DSI_CONTROL_TXMD;
 
-	if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
+	if (!(dsi_dev->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
 		val |= TC358768_DSI_CONTROL_HSCKMD;
 
 	if (dsi_dev->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET)

-- 
2.43.0